Effects of TiO2 content and crystallization treatments on elastic modulus of alkali-free aluminosilicate glass.

In this work, we focused on studying the effects of TiO 2 content and crystallization treatment on the elastic modulus of alkali-free aluminosilicate glass in the CaO–MgO–Al 2 O 3 –SiO 2 (CMAS) system. Five groups of alkali-free CMAS parent glass with different TiO 2 (0.30–1.50 wt%) components were designed, and several kinds of measurements including of Fourier-transform infrared spectrophotometer (FTIR), differential scanning calorimetry (DSC), x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and elastic modulus tests were carried out to evaluate the performance of both parent glass and glass-ceramics samples. The results show the elastic modulus of alkali-free parent glass decreased gradually with the TiO 2 content increased from 0.30 to 1.50 wt%, the maximum value of elastic modulus was 91.62 ± 0.80 GPa for T-1# sample (0.30 wt% TiO 2) and it decreased to 77.99 ± 1.73 GPa for T-5# sample (1.50 wt% TiO 2). The crystallization kinetics analysis of both T-1# and T-5# parent glass indicate the parent glass is in favor to surface crystallization. After the heat treatment at 1000–1150 °C for crystallization, the major crystal phase of both T-1# and T-5# group glass-ceramics was found to be anorthite (CaAl 2 Si 2 O 8), with the crystal sizes around 200–500 nm. However, the crystallization treatments have shown different influence on the elastic modulus of T-1# and T-5# parent glass. The elastic modulus value of T-1# group glass-ceramics gradually decreased from 91.62 ± 0.80 GPa to 80.22 ± 2.84–90.82 ± 4.27 GPa after crystalized at 1000–1150 °C. On the contrary, the elastic modulus value of T-5# group glass-ceramics increased from 77.99 ± 1.73 GPa to 80.50 ± 4.57–88.91 ± 6.44 GPa after crystalized at 1000–1150 °C. This results further confirmed that the elastic modulus values of glass-ceramics main depends on the parent glass and the crystal phase in glass-ceramics. The effects of TiO 2 content and crystallization process on elastic modulus of alkali-free CMAS parent glass was investigated. Whether the crystallization process could enhance the elastic modulus values of glass-ceramics main depends on the parent glass and the crystal phase in glass-ceramics. [Display omitted] • The elastic modulus of parent glass decreasing with increased of TiO 2 content. • The parent glass prefers surface crystallization and precipitates anorthite phase. • Glass-ceramics elastic modulus depends on the content of glass and crystal phase. • The elastic modulus of T-5# glass show an increasing trend after crystallization. [ABSTRACT FROM AUTHOR]